Flight 1487 left O'Hare at 10:53 a.m. and returned to the airport at 12:13 p.m. after the Boeing 737-800 plane developed a "fuel cross feed problem" which involves keeping the fuel in balance during the flight, according to American Airlines Spokeswoman Mary Frances Fagan.

The pilot declared an emergency because he had more fuel than usual for a landing, said Fagan. The plane returned to the airport normally and no one was injured, said Fagan.

The flight was eventually cancelled and the passengers were being put on another airplane scheduled to leave at 4:50 p.m.